Adventures of Oxygen Clip Chemical Bonding 1 Adventures of Oxygen Clip

2 GOALS 1. Compare & contrast ionic and covalent bonds in terms of electron position. 2. Predict formulas for stable binary ionic compounds based on balance of charges. 3. Determine the Types of ions formed by representative elements 4. Use IUPAC nomenclature for transition between chemical names and chemical formulas of - binary ionic compounds - binary covalent compounds 34 16 (IUPAC) International Union of Pure and Applied Chemistry

Why do Atoms Form Compounds? 3 Stability. What makes an atom stable? Full outer energy level. Eight. They can either…… 1) Gain electrons 2) Lose electrons 3) Share electrons

4 A Chemical Bond holds atoms together in a compound. Two basic types: 1. Ionic 2. Covalent

Ionic Bonding Transfer of electrons from one atom to another atom. 5 Ionic Bonding Transfer of electrons from one atom to another atom. Occurs between metals & nonmetals. Remember: Atoms need a full outer energy level to be stable. EIGHT! Called compounds.

Ionic Bonding Opposites ATTRACT! Occurs between metals and nonmetals. 6 Ionic Bonding Occurs between metals and nonmetals. Metals are electron donors. SO, they become POSITIVE Non-metals are electron accepters. SO, they become NEGATIVE. Opposites ATTRACT!

When Atoms gain or lose electrons, they are called Ions. 3P 3P 3P Anion 3P 3P 3P Cation

Metals lose electrons to become stable. Nonmetals gain electrons to become stable.

Ionization: requires energy Why do atoms lose and gain electrons? Atoms can gain or lose electrons Ionization: requires energy Why do atoms lose and gain electrons? To become more stable. Stability=full outer energy level

11 Animation Examples Opposites Attract!

Properties of Ionic Compounds 12 Properties of Ionic Compounds Crystalline solids at room temperature. Arranged in repeating three-dimensional patterns Have high melting points Can conduct electricity when melted or dissolved in water

13 Ionic Bonding CLIP

Occurs between nonmetals and nonmetals. 14 Covalent Bonding Occurs between nonmetals and nonmetals. The sharing of electrons between atoms. Called Molecules.

15

16 Hydrogen and Fluorine Hydrogen and Chlorine

17 Single, Double, Triple 2 e- 4e- 6e-

18 Clip

Polar molecules happen when one atom has a greater positive charge 19 Unequal Sharing Called Polar δ+ δ_ Polar molecules happen when one atom has a greater positive charge

Properties of Covalent Molecules 20 Properties of Covalent Molecules Many are gases or liquids at room temperature Composed of two nonmetals. Have low melting and boiling points… covalent bonds are weaker than ionic bonds

Covalent or Ionic? (write the formula, then write “C” or “I”) 21 Covalent or Ionic? (write the formula, then write “C” or “I”) CO2 NaCl H2O MgCl2 NO2 Li2S NaF BeCl2 BeO HCl KCl H2O2 N2 Cl2 AgCl2 clip

Ionic and Covalent Bonding Review Clip

Writing Chemical Formulas Goals revisited

22 The chemical formula for water is H2O. Carbon Dioxide is CO2. Writing chemical formulas is a shorthand way of indicating what a substance is made of.  These formulas also let you know how many atoms of each type are found in a molecule.  The chemical formula for water is H2O.  Carbon Dioxide is CO2.  Why does oxygen combine in different ratios, in different compounds?  The chemical formula for table salt is NaCl. Calcium Chloride is CaCl2. Why does chlorine combine in different ratios, in different compounds? 

The simplest compounds are ones with only two elements 23 The simplest compounds are ones with only two elements These are called binary KI, CO, H2O, NaCl

Oxidation numbers +4 -4 +1 Tell you how many electrons an atom must gain, lose or share to become stable. -2 +2 +3 -3 -1 24

All compounds are neutral That means the overall charge is ZERO! 25 Oxidation numbers We can predict the ratio of atoms in ionic compounds based on their oxidation numbers +1 -1 1 valence electron K Cl 7 valence electron All compounds are neutral Tells you how many electrons an atom must gain, lose or share to become stable. KCl That means the overall charge is ZERO!

To make it ZERO, you need 1 Ca & 2 Br. +1 -1 +2 -1 Na Br Ca Br To make it ZERO, you need 1 Ca & 2 Br. NaBr CaBr2 Subscripts show the number of atoms of that kind in the compound 26

Now You Try writing Binary Ionic formulas 27 Now You Try writing Binary Ionic formulas K + Br Mg + Cl Ca + I K + O K + I Sr + Br Na + O Ga + Br

Some elements have more than one oxidation number (Chart p588) +3 -2 +2 -2 Co O Co O Co2O3 CoO We call these elements- Multivalent Elements 28

29 Multivalent Practice Fe+2 + O Fe+3 + S Cu+2 + F Cr+3 + Br

Naming Chemical Formulas

Naming Binary Compounds and Molecules 32 Steps: If it is Binary- Decide if it is an ionic or covalent bond. Metal- nonmetal….. Ionic Nonmetal- nonmetal…. Covalent Example: NaCl

If ionic ……. Examples: CaO K2S NaCl K2O AlCl3 BaF2 33 Example: NaCl With a friend: NaCl K2O AlCl3 BaF2 Check to see if any elements are multivalent. If all single valent, write the name of the positive ion first. Write the root of the negative ion and add –ide.

If ionic ……. 34 Check to see if any elements are multivalent. If multivalent ions, determine the oxidation number of the element. Use Roman numerals in parentheses after the name of the element. Write the root of the negative ion and add –ide. NiCl Mn2S

Ionic-multivalent Examples: FeO Fe2O3 CuO Cu2O

36 If Covalent... Use Greek prefix to indicate how many atoms of each element are in the molecule Add -ide to the more electronegative element Greek Prefixes 1- mono- 2- di- 3- tri- 4- tetra- 5- penta- 6- hexa- 7- hepta- 8- octa- Example: PCl3 Phosphorous trichloride NO Nitrogen Monoxide

Naming Covalent Practice 36 ¾ Naming Covalent Practice P4S5 SF6 N2O5 H2O NF3 SiO2 P2Br4 SO3 Tetraphosphorus Pentasulfide Sulfur Hexafluoride Dinitrogen Pentaoxide Dihydrogen Monoxide Nitrogen Trifluoride Silicon Dioxide Diphosphorus Tetrabromide Sulfur Trioxide Greek Prefixes 1- mono- 2- di- 3- tri- 4- tetra- 5- penta- 6- hexa- 7- hepta- 8- octa-

Name the following: Mixed Practice 37 Name the following: Mixed Practice KBr HCl MgO CaCl2 H2O NO2 Potassium Bromide Hydrogen Monochloride Magnesium Oxide Calcium Chloride Dihydrogen Monoxide Nitrogen Dioxide Calcium Sulfide Chromium (III) Oxide Iron (II) Oxide Lithium Bromide CaS Cr2O3 FeO LiBr

End of Chemical Bonding Study Packet

38 Writing & Balancing Chemical Equations Goals revisited

GOALS 1. Apply the Law of Conservation of Matter by balancing following types of chemical equations: Synthesis Decomposition Single Replacement Double Replacement 2. Demonstrate the Law of Conservation of Matter in a chemical reaction

39 Chemical Reactions A chemical reaction is a change in which one or more substances are converted into new substances. Rearrangement of bonds in compounds and molecules. Chemical Equations make it possible to see clearly what is happening during a chemical reaction

Chemical equations are a shorthand way to show chemical reactions. 40 Chemical equations are a shorthand way to show chemical reactions. Reactants Products H2 + O2 H2O

The mass of the products always equals the mass of the reactants 41 Conservation of Mass The mass of the products always equals the mass of the reactants

2 Hydrogen atoms & one Oxygen atom 42 H2 + O2 H2O Does this meet the Conservation of Mass Law? 2 Hydrogen atoms 2 Oxygen atoms 2 Hydrogen atoms & one Oxygen atom Must Balance the Equation to show Conservation of Mass.

43 Can add coefficients to Balance equations. 2 H2 + O2 2 H2O 4 2 2 2 4 2 1 Balanced!! Steps: 1. Count Atoms on both sides 2. If not Balanced, add coefficients to balance. 3. Recount atoms after adding each coefficient. 4. Keep adding coefficients until balanced.

Types of Chemical Reactions 44

45 Chemical Reactions You start with one or more compounds and turn it into different compounds. Vapors of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride.

Single Replacement (Single Displacement) 46 Synthesis Decomposition Single Replacement (Single Displacement) Double Replacement (Double Displacement)

Synthesis “to make” A + B AB 2Cu + O2 2CuO 2H2 + O2 2H2O

Decomposition 2H2O 2H2 + O2 NaOH Na + OH AB A + B “to breakdown” Animation Decomposition “to breakdown” AB A + B 2H2O 2H2 + O2 NaOH Na + OH

When one element replaces another element in a compound Single Replacement When one element replaces another element in a compound A + BC AC + B Cu+AgNO3 Cu(NO3)2+ 2Ag The more reactive metal will always replace the less reactive metal. (p749)

Single Replacement Clip

Double Replacement AB + CD AD + CB Ba(NO3)2+KSO4 2KNO3 + BaSO4 Positive Ion of One compound replaces the positive ion of another compound and a Precipitate is formed. AB + CD AD + CB Ba(NO3)2+KSO4 2KNO3 + BaSO4 Review Clip

Clip Animation

Review Clip

Combustion

Chemical Reactions and Energy

Chemical Reactions and Energy 51 Chemical Reactions and Energy All chemical reactions release or absorb energy. Heat, light, sound Chemical reactions are the making and breaking or bonds.

1. Exergonic Chemical reactions that releases energy are called exergonic. Glow sticks If heat is released, it is called exothermic.

2. Endergonic Chemical reactions that require energy are called endergonic. Ex: Cold Packs If heat is absorbed, it is called endothermic

Catalysts and Inhibitors Some reactions proceed slowly. They can be sped up by a catalysts. Catalysts are not used up in the reaction. EX: enzymes (biological catalysts) Some reactions proceed too fast. They can be slowed down by inhibitors. EX: Preservatives in food

GOALS Revisited….. 1. Compare & contrast ionic and covalent bonds in terms of electron position. 2. Predict formulas for stable binary ionic compounds based on balance of charges. 3. Use IUPAC nomenclature for transition between chemical names and chemical formulas of • binary ionic compounds • binary covalent compounds 4. Apply the Law of Conservation of Matter by balancing the following types of chemical equations: • Synthesis • Decomposition • Single Replacement • Double Replacement